1)I studied chronological medieval rooftiles and divided eight stages, They are first stage (from 1180 to 1210), second stage (from 1210 to 1260), third stage (from 1260 to 1300), fourth stage (from 1300 to 1333), fifth stage (from 1333 to 1380), sixth stage (from 1380 to 1430), seventh stage (from 1430 to 1500) and eighth stage (from 1500 to 1575). Medieval rooftile production techniques is more definite than ancient rooftile production techniques in individual stage.2)I studied medieval rooftiles which are made by the same wooden mold. Medieval rooftiles made by the same mold fall into two types. The first type is removal of the rooftiles. For example, rooftiles in Todai Temple were carried from Bizen in first stage. Rooftiles in Toji Temple were carried from Harima in first stage. Rooftiles in many Kamakura's Temples were carried from Owari, Izu, Kyoto, Musashi and Izumi (modern Sakai) in first and second stages. The second type is produced by tile workers who have been transfered. Yamato's tile workers produced many rooftiles in Onomichi's Jodoji Temple, Harima's Enkyoji Temple, Kii's Negoroji Temple and Kawachi's Rijusenji Temple.3)There are three rooftile production systems in medieval Japan, The first system is Yamato type. The second system is Kyoto type. The last system is Osaka type. These three type systems have great influence on Japanese medieval rooftile productions.